This research will describe and explain changes from 1970 to 1980 in the gap between city and suburban average incomes, for each of the 100 largest metropolitan areas in the United States. Income is an important measure of individual and community well-being, and the disparity between average incomes in large central cities and their suburban rings is at once a consequence and a cause of urban development patterns. Empirical analysis in the project will be both descriptive and causal. The discriptive portion will disaggregate the change from 1970 to 1980 in the ratio of city-to-suburb average household income, to determine how much of the change is attributable to change in SMSA-wide population composition and how much is attributable to changes in intrametropolitan location choice of specific household types and racial groups. This portion of the analysis will integrate the literature on (1) demographic aspects of economic well-being, and (2) the changing household composition of metropolitan America. The causal analysis will apply recent urban theory in generating and testing hypotheses about change in the city/suburb income ratio. This part of the analysis will emphasize the contrasts between the traditional explanations for a declining relative income level for cities and the more recent speculations regarding urban revitalization.